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<tr class="t-nv-h1"><td colspan="5"> 成员函数</td></tr>
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<table class="t-dcl-begin"><tbody>
<tr class="t-dsc-header">
<td> <div>定义于头文件 <code><a href="../header/string.html" title="cpp/header/string">&lt;string&gt;</a></code>
 </div></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span><br>
<p>    <span class="kw1">class</span> CharT <br>
</p>
<span class="sy1">&gt;</span> <span class="kw1">class</span> char_traits<span class="sy4">;</span></span></div></td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep"><td></td><td></td><td></td></tr>
</tbody></table>
<p><code>char_traits</code> 类是一种特性类模板，对给定的字符类型抽象基础字符和字符串比较操作。有定义操作集是几乎始终可实现于其项的通用算法。从而可以将这些算法用于几乎任何可能的字符或字符串类型，只需提供自定义的 <code>char_traits</code> 类。
</p><p><code>char_traits</code> 类模板表现为显式实例化的基础。用户可以对任何自定义字符类型<a href="../language/extending_std.html" title="cpp/language/extending std">提供特化</a>。标准字符类型上已定义了数种特化。
</p>
<h3><span class="mw-headline" id=".E6.A0.87.E5.87.86.E7.89.B9.E5.8C.96">标准特化</span></h3>
<p>标准特化的成员 typedef 定义如下。
</p>
<table class="t-dsc-begin">

<tr class="t-dsc-hitem">
<th> 特化
</th>
<th> <code>char_type</code>
</th>
<th> <code>int_type</code>
</th>
<th> <code>pos_type</code>
</th></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span><span class="kw4">char</span><span class="sy1">&gt;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">char</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">int</span></span></span>
</td>
<td> <span class="t-lc"><a href="../io/fpos.html" title="cpp/io/fpos">std::streampos</a></span>
</td></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span><span class="kw4">wchar_t</span><span class="sy1">&gt;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">wchar_t</span></span></span>
</td>
<td> <span class="t-lc">std::wint_t</span>
</td>
<td> <span class="t-lc"><a href="../io/fpos.html" title="cpp/io/fpos">std::wstreampos</a></span>
</td></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span><span class="kw4">char16_t</span><span class="sy1">&gt;</span></span></span> <span class="t-mark-rev t-since-cxx11">(C++11)</span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">char16_t</span></span></span>
</td>
<td> <span class="t-lc"><a href="../types/integer.html" title="cpp/types/integer">std::uint_least16_t</a></span>
</td>
<td> <span class="t-lc"><a href="../io/fpos.html" title="cpp/io/fpos">std::u16streampos</a></span>
</td></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span><span class="kw4">char32_t</span><span class="sy1">&gt;</span></span></span> <span class="t-mark-rev t-since-cxx11">(C++11)</span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">char32_t</span></span></span>
</td>
<td> <span class="t-lc"><a href="../types/integer.html" title="cpp/types/integer">std::uint_least32_t</a></span>
</td>
<td> <span class="t-lc"><a href="../io/fpos.html" title="cpp/io/fpos">std::u32streampos</a></span>
</td></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span>char8_t<span class="sy1">&gt;</span></span></span> <span class="t-mark-rev t-since-cxx20">(C++20)</span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">char8_t</span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">unsigned</span> <span class="kw4">int</span></span></span>
</td>
<td> <span class="t-lc">std::u8streampos</span>
</td></tr></table>
<table class="t-dsc-begin">

<tr class="t-dsc-hitem">
<th> 成员类型
</th>
<th> 定义（对所有标准特化相同）
</th></tr>
<tr class="t-dsc">
<td> <code>off_type</code>
</td>
<td> <span class="t-lc"><a href="../io/streamoff.html" title="cpp/io/streamoff">std::streamoff</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>state_type</code>
</td>
<td> <span class="t-lc"><a href="multibyte/mbstate_t.html" title="cpp/string/multibyte/mbstate t">std::mbstate_t</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>comparison_category</code> <span class="t-mark-rev t-since-cxx20">(C++20)</span>
</td>
<td> <span class="t-lc">std::strong_ordering</span>
</td></tr></table>
<p>标准特化的成员函数的语义定义如下：
</p>
<table class="t-dsc-begin">

<tr class="t-dsc-hitem">
<th> 特化
</th>
<th> <code>assign</code>
</th>
<th> <code>eq</code>
</th>
<th> <code>lt</code>
</th>
<th> <code>eof</code>
</th></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span><span class="kw4">char</span><span class="sy1">&gt;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">=</span></span></span>
</td>
<td> <code>unsigned char</code> 的 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">==</span></span></span>
</td>
<td> <code>unsigned char</code> 的 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">&lt;</span></span></span>
</td>
<td> <span class="t-lc"><a href="../io/c.html" title="cpp/io/c">EOF</a></span>
</td></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span><span class="kw4">wchar_t</span><span class="sy1">&gt;</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">=</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">==</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">&lt;</span></span></span>
</td>
<td> <span class="t-lc">WEOF</span>
</td></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span><span class="kw4">char16_t</span><span class="sy1">&gt;</span></span></span> <span class="t-mark-rev t-since-cxx11">(C++11)</span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">=</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">==</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">&lt;</span></span></span>
</td>
<td> 非法 UTF-16 编码单元
</td></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span><span class="kw4">char32_t</span><span class="sy1">&gt;</span></span></span> <span class="t-mark-rev t-since-cxx11">(C++11)</span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">=</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">==</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">&lt;</span></span></span>
</td>
<td> 非法 UTF-32 编码单元
</td></tr>
<tr class="t-dsc">
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span>char8_t<span class="sy1">&gt;</span></span></span> <span class="t-mark-rev t-since-cxx20">(C++20)</span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">=</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">==</span></span></span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">&lt;</span></span></span>
</td>
<td> 非法 UTF-8 编码单元
</td></tr></table>
<p><code>char_traits</code> 类模板的标准特化满足<a href="../named_req/CharTraits.html" title="cpp/named req/CharTraits"><span style="font-style:italic">字符特征</span> <span style="font-family: Georgia, 'DejaVu Serif', serif; font-style:italic">(CharTraits)</span> </a>的要求。
</p>
<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E7.B1.BB.E5.9E.8B">成员类型</span></h3>
<table class="t-dsc-begin">

<tr class="t-dsc-hitem">
<td>  类型
</td>
<td>  定义
</td></tr>


<tr class="t-dsc">
<td>  <code>char_type</code>
</td>
<td>  <code>CharT</code>
</td></tr>


<tr class="t-dsc">
<td>  <code>int_type</code>
</td>
<td>  能保有所有 <code>char_type</code> 值加 <code>EOF</code> 的整数类型
</td></tr>


<tr class="t-dsc">
<td>  <code>off_type</code>
</td>
<td>  <i>实现定义</i>
</td></tr>


<tr class="t-dsc">
<td>  <code>pos_type</code>
</td>
<td>  <i>实现定义</i>
</td></tr>


<tr class="t-dsc">
<td>  <code>state_type</code>
</td>
<td>  <i>实现定义</i>
</td></tr>

</table>
<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">成员函数</span></h3>
<table class="t-dsc-begin">

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/assign.html" title="cpp/string/char traits/assign"> <span class="t-lines"><span>assign</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   赋值一个字符 <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/cmp.html" title="cpp/string/char traits/cmp"> <span class="t-lines"><span>eq</span><span>lt</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   比较二个字符  <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/move.html" title="cpp/string/char traits/move"> <span class="t-lines"><span>move</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   移动一个字符序列到另一个上 <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/copy.html" title="cpp/string/char traits/copy"> <span class="t-lines"><span>copy</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   复制一个字符序列 <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/compare.html" title="cpp/string/char traits/compare"> <span class="t-lines"><span>compare</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   以字典序比较二个字符序列 <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/length.html" title="cpp/string/char traits/length"> <span class="t-lines"><span>length</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   返回一个字符序列的长度 <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/find.html" title="cpp/string/char traits/find"> <span class="t-lines"><span>find</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   在字符序列中查找一个字符 <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/to_char_type.html" title="cpp/string/char traits/to char type"> <span class="t-lines"><span>to_char_type</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   转换 <code>int_type</code> 到等效的  <code>char_type</code> <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/to_int_type.html" title="cpp/string/char traits/to int type"> <span class="t-lines"><span>to_int_type</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   转换 <code>char_type</code> 到等效的  <code>int_type</code> <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/eq_int_type.html" title="cpp/string/char traits/eq int type"> <span class="t-lines"><span>eq_int_type</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   比较二个 <code>int_type</code> 值 <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/eof.html" title="cpp/string/char traits/eof"> <span class="t-lines"><span>eof</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   返回一个 <i>eof</i> 值 <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="char_traits/not_eof.html" title="cpp/string/char traits/not eof"> <span class="t-lines"><span>not_eof</span></span></a></div><div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div></div>
</td>
<td>   检查字符是否为 <i>eof</i> 值 <br> <span class="t-mark">(公开静态成员函数)</span> </td></tr>
</table>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
<div class="t-example"><p>用户定义的字符特性可以用于提供<a rel="nofollow" class="external text" href="http://www.gotw.ca/gotw/029.htm">无关大小写的比较</a></p><div class="t-example-live-link"><div class="coliru-btn coliru-btn-run-init">运行此代码</div></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;string&gt;</span>
<span class="co2">#include &lt;string_view&gt;</span>
<span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;cctype&gt;</span>
 
<span class="kw1">struct</span> ci_char_traits <span class="sy4">:</span> <span class="kw1">public</span> std<span class="sy4">::</span><span class="me2">char_traits</span><span class="sy1">&lt;</span><span class="kw4">char</span><span class="sy1">&gt;</span> <span class="br0">{</span>
    <span class="kw4">static</span> <span class="kw4">char</span> to_upper<span class="br0">(</span><span class="kw4">char</span> ch<span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">toupper</span><span class="br0">(</span><span class="br0">(</span><span class="kw4">unsigned</span> <span class="kw4">char</span><span class="br0">)</span> ch<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">static</span> <span class="kw4">bool</span> eq<span class="br0">(</span><span class="kw4">char</span> c1, <span class="kw4">char</span> c2<span class="br0">)</span> <span class="br0">{</span>
         <span class="kw1">return</span> to_upper<span class="br0">(</span>c1<span class="br0">)</span> <span class="sy1">==</span> to_upper<span class="br0">(</span>c2<span class="br0">)</span><span class="sy4">;</span>
     <span class="br0">}</span>
    <span class="kw4">static</span> <span class="kw4">bool</span> lt<span class="br0">(</span><span class="kw4">char</span> c1, <span class="kw4">char</span> c2<span class="br0">)</span> <span class="br0">{</span>
         <span class="kw1">return</span> to_upper<span class="br0">(</span>c1<span class="br0">)</span> <span class="sy1">&lt;</span>  to_upper<span class="br0">(</span>c2<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">static</span> <span class="kw4">int</span> compare<span class="br0">(</span><span class="kw4">const</span> <span class="kw4">char</span><span class="sy2">*</span> s1, <span class="kw4">const</span> <span class="kw4">char</span><span class="sy2">*</span> s2, <a href="../types/size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> n<span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">while</span> <span class="br0">(</span> n<span class="sy2">--</span> <span class="sy3">!</span><span class="sy1">=</span> <span class="nu0">0</span> <span class="br0">)</span> <span class="br0">{</span>
            <span class="kw1">if</span> <span class="br0">(</span> to_upper<span class="br0">(</span><span class="sy2">*</span>s1<span class="br0">)</span> <span class="sy1">&lt;</span> to_upper<span class="br0">(</span><span class="sy2">*</span>s2<span class="br0">)</span> <span class="br0">)</span> <span class="kw1">return</span> <span class="sy2">-</span><span class="nu0">1</span><span class="sy4">;</span>
            <span class="kw1">if</span> <span class="br0">(</span> to_upper<span class="br0">(</span><span class="sy2">*</span>s1<span class="br0">)</span> <span class="sy1">&gt;</span> to_upper<span class="br0">(</span><span class="sy2">*</span>s2<span class="br0">)</span> <span class="br0">)</span> <span class="kw1">return</span> <span class="nu0">1</span><span class="sy4">;</span>
            <span class="sy2">++</span>s1<span class="sy4">;</span> <span class="sy2">++</span>s2<span class="sy4">;</span>
        <span class="br0">}</span>
        <span class="kw1">return</span> <span class="nu0">0</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">static</span> <span class="kw4">const</span> <span class="kw4">char</span><span class="sy2">*</span> find<span class="br0">(</span><span class="kw4">const</span> <span class="kw4">char</span><span class="sy2">*</span> s, <a href="../types/size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> n, <span class="kw4">char</span> a<span class="br0">)</span> <span class="br0">{</span>
        <span class="kw4">auto</span> <span class="kw4">const</span> ua <span class="br0">(</span>to_upper<span class="br0">(</span>a<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
        <span class="kw1">while</span> <span class="br0">(</span> n<span class="sy2">--</span> <span class="sy3">!</span><span class="sy1">=</span> <span class="nu0">0</span> <span class="br0">)</span> 
        <span class="br0">{</span>
            <span class="kw1">if</span> <span class="br0">(</span>to_upper<span class="br0">(</span><span class="sy2">*</span>s<span class="br0">)</span> <span class="sy1">==</span> ua<span class="br0">)</span>
                <span class="kw1">return</span> s<span class="sy4">;</span>
            s<span class="sy2">++</span><span class="sy4">;</span>
        <span class="br0">}</span>
        <span class="kw1">return</span> nullptr<span class="sy4">;</span>
    <span class="br0">}</span>
<span class="br0">}</span><span class="sy4">;</span>
 
<span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> DstTraits, <span class="kw1">class</span> CharT, <span class="kw1">class</span> SrcTraits<span class="sy1">&gt;</span>
<span class="kw4">constexpr</span> <a href="basic_string_view.html"><span class="kw1246">std::<span class="me2">basic_string_view</span></span></a><span class="sy1">&lt;</span>CharT, DstTraits<span class="sy1">&gt;</span>
    traits_cast<span class="br0">(</span><span class="kw4">const</span> <a href="basic_string_view.html"><span class="kw1246">std::<span class="me2">basic_string_view</span></span></a><span class="sy1">&lt;</span>CharT, SrcTraits<span class="sy1">&gt;</span> src<span class="br0">)</span> <span class="kw1">noexcept</span>
<span class="br0">{</span>
    <span class="kw1">return</span> <span class="br0">{</span>src.<span class="me1">data</span><span class="br0">(</span><span class="br0">)</span>, src.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span>
 
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
    <span class="kw1">using</span> <span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">literals</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> s1 <span class="sy1">=</span> <span class="st0">"Hello"</span>sv<span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> s2 <span class="sy1">=</span> <span class="st0">"heLLo"</span>sv<span class="sy4">;</span>
 
    <span class="kw1">if</span> <span class="br0">(</span>traits_cast<span class="sy1">&lt;</span>ci_char_traits<span class="sy1">&gt;</span><span class="br0">(</span>s1<span class="br0">)</span> <span class="sy1">==</span> traits_cast<span class="sy1">&lt;</span>ci_char_traits<span class="sy1">&gt;</span><span class="br0">(</span>s2<span class="br0">)</span><span class="br0">)</span>
        <a href="../io/cout.html"><span class="kw1757">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> s1 <span class="sy1">&lt;&lt;</span> <span class="st0">" and "</span> <span class="sy1">&lt;&lt;</span> s2 <span class="sy1">&lt;&lt;</span> <span class="st0">" are equal<span class="es1">\n</span>"</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<p>输出：
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="text source-text"><pre class="de1">Hello and heLLo are equal</pre></div></div> 
</div>
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
<table class="t-dsc-begin">

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="basic_string.html" title="cpp/string/basic string"> <span class="t-lines"><span>basic_string</span></span></a></div></div>
</td>
<td>   存储并操作字符序列 <br> <span class="t-mark">(类模板)</span> </td></tr>
</table>

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